Eappendix time-window bias in case-control studies: statins and lung cancer samy suissa, sophie dell'aniello, sarah vahey and christel renoux - 1 - magnitude of the bias. Design case-control study setting uk clinical practice research datalink primary care data to explore whether the association between our risk factors of interest and zoster could be affected by ascertainment bias suissa s, dell’aniello s, vahey s, renoux c time-window bias in case-control studies: statins and lung cancer. In contrast, four controlled, randomized statin trials have resulted in a statistically significant increase of cancer in the treatment group and several case–control and cohort studies have also shown a significant risk of cancer associated with statins.
While this may be an improvement over the breast cancer study , this method is still prone to time-window bias length of time in the database simply means that cases and matched controls have been registered in the database for the same amount of time. While some animal models, epidemiological studies and randomized trials suggest that statins may be carcinogenic,1, 2, 3 new laboratory data show that they have antiproliferative, proapoptotic and antiinvasive properties,4 and recent observational studies report inverse statin-cancer associations5, 6, 7 in contrast, neither the cholesterol. Case definition and design sensitivity in case-control studies (us) were launching observational studies on effect of smoking on lung cancer doll and hill (1950) non-smokers smokers protectors against bad cholesterol • case control study to look for genotypes that protect.
Lung cancer (lc) is a major cause of cancer death world- three studies were case-control studies and five studies were cohort studies three studies were when we limited the meta-analysis to studies that con-trolled for statins or smoking, the result was changed (table 2. The publications were classified according to the potential bias induced by the study design, including immortal time bias, immeasurable time bias, selection bias, and confounding (all described in the following text in the context of selected studies. Proton pump inhibitors do not reduce the risk of esophageal adenocarcinoma in patients with barrett’s esophagus: a systematic review and meta-analysis c time-window bias in case-control studies: statins and lung cancer epidemiology 201122(2):228–31 proton pump inhibitors) and the risk of esophageal adenocarcinoma in patients. This ensures that both patients and controls have observation periods of the same lengths and thus avoids time-window bias 5 one of the major limitations in the studies analyzing large health care claims databases is the etal: time-window bias in case-control studies statins and lung cancer epidemiology 22: 228 – 231, 2011 crossref. Finally, seven studies reporting the effect of statins on type 2 diabetes mellitus patients were included in present analysis among the 7 studies enrolling a total of 23,555 participants, 2 studies are random control trials and 5 studies are case-control studies [34–40] table 1 shows the characteristics of study.
Statins are commonly used cholesterol-lowering agents that are noted to suppress tumor cell growth in several in vitro and animal models statins reduce the risk of lung cancer in humans - chest. Abstract background: preclinical evidence from lung cancer cell lines and animal models suggest that statins could have anticancer properties we investigated whether statin users had reduced risk of cancer-specific mortality in a population-based cohort of lung cancer patients. Case-control studies contribute greatly to the research toolbox of an epidemiologist they embody the strengths and lung cancer, therefore, people with lung cancer are case-control study of oral contraceptive use and transmission of hiv-1 would be impractical in parts of.
Case-control 5,835 statins-liver cancer relationship liver cancer trial cancer  in a nested case-control study of 483 733 patients, statins appeared to be protective for the development of lung cancer statin use for ≥ 6 months demonstrated a cancer risk reduction by 55% (odds ratio [or] 045, 95% ci, 042 to 048, p 001). In lung cancer cell lines treated with simvastatin, and an in vivo study (10), using a mouse model, demonstrated reduced tumor growth and bone metastases after simvastatin treatment. They identified 22,163 patients with colon cancer (cases) and 86,539 patients without colon cancer (controls) and compared the levels of serum cholesterol levels between the two groups their results revealed that indeed, there was a decreased risk of colorectal cancer with concomitant statin use. A prior description of this bias showed the importance of measuring exposure among cases and controls using an equal time window [3 x  suissa, s, dell’aniello, s, vahey, s, and renoux, c time-window bias in case-control studies: statins and lung cancer. The included studies examined the association between statin use in patients with cancer of the prostate, lung, pancreas, oesophagus, kidney, breast, colon, lymphoma (b cell, t cell and non-hodgkin) and non-specified cancer type.
Objective: to investigate whether the use of statins was associated with kidney cancer risk methods: we conducted a population-based case–control study in taiwan cases consisted of all patients who were aged 50 years and older, and had a first-time diagnosis of kidney cancer for the period between 2005 and 2009. Three other studies in younger women in the united states (case-control surveillance study, 48 nurses’ health study, 49 and a population-based case-control study of 3 washington counties 50) showed no significant reduction of the risk for invasive breast cancer (rr ranged from 09 to 12. Importance patients with cancer who use statins appear to have a substantially better survival than nonusers in observational studies however, this inverse association between statin use and mortality may be due to selection bias and immortal-time bias objective to emulate a randomized trial of statin therapy initiation that is free of selection bias and immortal-time bias. Association between statin use and survival in lung cancer patients a recent danish study(11) observed some evidence of a weak reduction in cancer-specific mortality in individuals who used statins before lung cancer diagnosis (hr=087 95% ci 083, 092) however, this study.
Considered to be risk factors for lung cancer, even though for a case-control study using odds ratios (or) the formula for criterion 2 is: or eric notebook confounding bias part ii and effect measure modification, discuss control of confounders in epidemiological studies. If someone began smoking after they got lung cancer, then you cannot say that smoking caused lung cancer less subject to bias than case-control studies because smokers vs non-smokers continuous: cholesterol levels often break continuous variable down into groups, eg low, med, high everyone has but different levels what is an. Time-related biases in pharmacoepidemiology samy suissa mcgill university and jewish general hospital montreal, canada lung cancer incidence by 45% •time-window bias 2 immortal time bias the example of copd copd: the ontario study • observational study (ontario health databases) • cohort of 22,620 patients hospitalised for copd. In this issue of epidemiology, suissa et al 1 describe the “time-window” bias in case-control studies as a consequence of defining exposure within time-windows of different lengths for cases and controls to illustrate the bias, the authors estimated the association between incident lung cancer and statin exposure.